Unmet need for mental health services is extraordinarily high among urban children of diverse racial/ethnic backgrounds. As overall need continues to rise, schools are fast becoming the main source of mental health services for children. Externalizing behavior disorders and anxiety disorders are highly prevalent in low-income urban children. Unfortunately, evidence-based interventions (EBI) for those disorders are seldom employed in urban schools. School-Wide Positive Behavior Support (SWPBS), a multi-level services delivery strategy that combines universal and targeted interventions, has been found to be effective in improving school climate, perceived school safety, and student reading scores. Targeted group cognitive behavioral therapy (GCBT) can be provided to at-risk and high-risk students as part of the SWPBS system. Unfortunately, SWPBS and GCBT are seldom employed in under-resourced urban schools, in part, because school districts do not have enough resources to contract outside providers with expertise in EBIs for behavioral health problems. Also, widespread deployment of EBIs to real world settings has been hampered by problems such as inadequate training of service providers and poor implementation fidelity. The creation of mechanisms for the training and support of counselors and other school personnel that focus on maintaining high implementation fidelity and integrity can facilitate a significant increase in the use of EBIs in urban schools and contribute to lowering behavioral health disparities. The overall purpose of this project is to determine whether school personnel implementing a two-tier SWPBS program for typically developing children and children with, or at risk for, externalizing or anxiety disorders, can implement the components of the program with the same level of fidelity and integrity and clinical effectiveness when they receive a Low Level of Support (LLS) from their coaches and supervisors as compared to a High Level of Support (HLS). We also want to determine whether school personnel who receive HLS for two years could continue to implement the components of the program with a similar level of fidelity and integrity and clinical effectiveness while receiving LLS during the following two years. We will calculate the total costs and net costs associated with the development and implementation of the SWPBS program. The study uses a cohort-sequential design and follows 6 separate K-8 schools in the Philadelphia School District, yielding approximately 48 leadership team members, 180 school personnel, and 3,900 students in Tier 1, and 12 counselors, 84 groups of 4-5 children with, or at risk for, oppositional defiant disorder or conduct disorder in each CBT group, and 3-4 children with, or at risk for, generalized anxiety disorder, separation anxiety disorder, o social phobia in each CBT group, for a total of 306 evaluable child participants. Schools will be randomly assigned to receive either HLS or LLS from project staff. The proposed study is consistent with the current strategic plan of the National Institute of Child Health and Human Development (NICHD), particularly the commitment to support research that addresses barriers to school readiness and academic success for minority and low-income children.